Clinical Hemorheology and Microcirculation - Volume 21, issue 3-4

Authors: Leonetti, Gastone | Zanchetti, Alberto

Article Type: Research Article

Citation: Clinical Hemorheology and Microcirculation, vol. 21, no. 3-4, pp. 217-224, 1999

Authors: Nazzaro, P. | Triggiani, R. | Ciancio, L. | Scarano, A.M. | Merlo, M. | Manzari, M. | Cicco, G. | Manicone, A. | Pirrelli, A.

Article Type: Research Article

Abstract: Office and ambulatory pulse pressure have been recognized as independent predictors of cardiovascular mortality and atherosclerosis in hypertensives as well as in normotensives. On the other hand, the vascular reactivity, in subjects with high pulsatile component of blood pressure, has not been studied yet. The purpose of our study was to identify the regional muscular hemodynamics and the cutaneous microvascular changes during laboratory stimuli in young adult very mild hypertensives with high pulse pressure. The cardiovascular (Finapres), the forearm vascular (plethysmography) and the microvascular cutaneous (laser‐Doppler flowmetry and transcutaneous oximetry) responses to psychophysiological stimuli were measured. In addition, the …hyperemic forearm vascular response to the ischaemic test was measured as haemodynamic index of vascular damage. We studied 15 very mild hypertensives with higher office pulse pressure and 15 patients with similar age, history of hypertension, metabolic parameters and systodiastolic blood pressure but lower pulse pressure values. Patients with high pulse pressure demonstrated reduced hyperemic response and increased residual vascular resistance at the forearm ischaemic test. They did not vary for all the parameters, except pulse pressure, during the baseline period but the total stress response, as residualized area‐under‐the‐curve, was notably different. Patients with higher office pulse pressure demonstrated a significant increased heart rate, systolic and pulsatile blood pressure reactivity. On the contrary, they showed a reduced forearm and cutaneous blood flow response combined to a reduced transcutaneous tissutal oxygenation. The findings suggest that the increased pulsatile component of blood pressure might be associated to structural and functional vascular impairments since the very early stages of hypertension in young adults without metabolic disorders. Show more

Citation: Clinical Hemorheology and Microcirculation, vol. 21, no. 3-4, pp. 225-232, 1999

Authors: Giannattasio, C. | Failla, M. | Grappiolo, A. | Calchera, I. | Grieco, N. | Gorgoglione, M.G. | Mancia, G.

Article Type: Research Article

Citation: Clinical Hemorheology and Microcirculation, vol. 21, no. 3-4, pp. 233-239, 1999

Authors: Colonna, Paolo | Chen, Lijun | Cadeddu, Christian | Caiati, Carlo | Iliceto, Sabino

Article Type: Research Article

Citation: Clinical Hemorheology and Microcirculation, vol. 21, no. 3-4, pp. 241-244, 1999

Authors: Brevetti, Gregorio | Corrado, Salvatore | Martone, Vincenzo Domenico | Di Donato, AnnaMaria | Silvestro, Antonio | Vanni, Luigi

Article Type: Research Article

Citation: Clinical Hemorheology and Microcirculation, vol. 21, no. 3-4, pp. 245-254, 1999

Authors: Dumas, Dominique | Latger, Véronique | Viriot, Marie‐Laure | Blondel, Walter | Stoltz, Jean‐François

Article Type: Research Article

Abstract: In this study, we measured the influence of cholesterol rigidification on oxygen permeability in human endothelial cell monolayer membranes (ECs). Cholesterol‐induced membrane rigidification was assessed at different membrane depths by a fluorescence polarization method with diphenyl‐hexatriene (DPH) and 1‐(4‐trimethylamino)‐6‐phenylhexatriene (TMA‐DPH). Fluorescence quenching by oxygen was probed in preferentially labelled membrane with pyrene butyric acid (PyC_{4} ) and pyrene dodecanoic acid (PyC_{12} ), as shown with a 3D fluorescence microscope (CellScanTM System). With both probes the experiments revealed a decrease in oxygen diffusion as the cholesterol concentration increased in the medium culture (from 3.42 \mu M to …17.11 \mu M). We showed that very low concentrations of cholesterol (about 1000 times below normal value, 6.2 mM) particularly decrease oxygen levels or diffusion rate in the middle region of the membrane. In conclusion, these findings prove in a direct manner that cholesterol significantly affect the endothelial barrier function and molecular oxygen transfer to underlying tissues. Risk factors (cholesterol) directly would contribute to tissue ischemia. Show more

Citation: Clinical Hemorheology and Microcirculation, vol. 21, no. 3-4, pp. 255-261, 1999

Authors: van der Kleij, A.J.

Article Type: Research Article

Citation: Clinical Hemorheology and Microcirculation, vol. 21, no. 3-4, pp. 263-266, 1999

Authors: Agabiti Rosei, Enrico | Rizzoni, Damiano

Article Type: Research Article

Citation: Clinical Hemorheology and Microcirculation, vol. 21, no. 3-4, pp. 267-272, 1999

Authors: Vulpis, Vito

Article Type: Research Article

Abstract: Although a large amount of data concerning microcirculation and cardiovascular disease exists, little is known about microcirculation and hypertension. This is largely due to the difficulty in selectively examining capillaries and metarterioles, independently from small arteries or large vessels. The physiological role of capillaries and metarterioles, the two elements that make up the microcycle, is peculiar and closely related to metabolic exchange. During the hypertensive state, several factors can alter these mechanisms. These include elevated plasma viscosity, abnormal membrane properties of red blood cells, and an increase in fibrinogen, LTL and hematocrit levels. The question of whether …an abnormal release of endothelium derived vasoactive factors from capillaries, or an abnormal production of chemical factors by blood cells running through the vasculature area is present in hypertensives is fascinating, but unfortunately neither experimental nor clinical data has yet been able to answer it. Recently, evidence of the formation of endothelin by red blood cells from endogenous precursors was given, suggesting that red blood cells may modulate the vascular tone both directly, through the release of ATP or endothelin‐1, and indirectly, when hemolysis occurs and hemoglobin is released. The pathological significance of these findings has not been clearly demonstrated in hypertension thus far, although it is reasonable to hypothesise that there are clinical implications for the pathogenesis and the progression of vascular damage during the hypertensive state. Show more

Citation: Clinical Hemorheology and Microcirculation, vol. 21, no. 3-4, pp. 273-276, 1999

Authors: Hardeman, M.R. | Ince, C.

Article Type: Research Article

Abstract: For many years the study of Red Blood Cell (RBC) deformability has been limited to specialised hematological research institutes and this has hampered a widespread clinical testing of this dynamic RBC property. Consequently, the clinical relevance of such in vitro measurements has remained questionable now for a considerable time. The recent availability of the LORCA, a routinely applicable and computer assisted instrument for this purpose, opens now the possibility to evaluate RBC deformability on a large scale in various pathological situations associated with impaired microcirculatory flow. In this communication we present our clinical experience obtained thusfar with this instrument. …Besides the effect of physiological aging of normal RBC, the results of a clinical study on malaria tropica, case studies of hereditary elliptocytosis, Smith–Lemli–Opitz syndrome (a cholesterol biosynthesis defect), the treatment of sickle cell crisis with hydroxy‐urea as well as the clinical intervention with Cyclosporin, are collected. In conclusion, it can be stated that the limited clinical experience with the LORCA as is reported here, yields sufficient evidence about the clinical potential of this technique. Show more

Citation: Clinical Hemorheology and Microcirculation, vol. 21, no. 3-4, pp. 277-284, 1999